Transformation of electric currents.



No. 869,695. PATENTED OCT. 29. 1907. W. T. TAYLOR. TRANSFORMATION OF ELECTRIC GURRBNTS.

APPLICATION FILED HARM. 1907.

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WTNESSES: J NVENTOR ATKYRNEY No. 869,595. 7 PATENTED OCT. 29. 1907.

W.. T. TAYLOR.

TRANSFORMATION OF ELECTRIC OURRENTS.

APPLICATION FILED MAB.14.190.7.

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\VlLLIAM TfTA-YLOR, OF OHIHUAHUli MEXIOO.

'rasnsr'o'amnrron or ELECTRIC coimnms.

No. season.

Specification of Letters Patent.

Patented Oct. 29, 1907.

i sertion filed much 14. 1907. smn No. 362.266.

To all whom it may concern:

Be it known that I, WILLIAM T. TAyLoiz, a citizen of the United States of America, and a resident of Chihuahua, in the-county of Chihuahua and country of Mexico, have invented certain new and useful Im-' provements in the Transformation of- Electric Currents, of which the following is a specification. T

The object of this invention is to meet a problem I which frequently arises in the distribution of electric energy by means of polyphase currents. It frequently happens that two-phase and threephase apparatus are found together upon the same system, as for example 'where two previously independent systems of distribution are consolidated, or where an installation of three-phase apparatus is changed from a three-phase to a two-phase system of supply or -the reverse. In such cases, according to practice as hitherto followed, one of two courses must be taken: Either there must be two separate sets-of distribution wire's,'one for threephase and the other for two-phase currents, or else the one general set of distribution wires for one system, and a special transformer or set of transformers at every point where there is a piece or group of apparatus adapted for the other system, to form a special secondary distribution system adapted thereto.

According to my invention I am enabled to derive both two-phase'and three-phase currents from a single set of four distribution wires from which either twophase or three-phase currents maybe tapped as desired;

and further, according to the most improved form or mode of carrying outthe invention, the phasesjn each 7 system are evenly balanced, and the drawing of ourrent of one kind from the system cannot unbalance it with respect to currents of the other kind.

My invention consists, generally speaking, in arranging an electrically energized three-phase transformer or system of transformers with a set offour. pecul- 'iarly disposed taps, in such manner th'at three of said taps taken together form a complete and perfect threephase system of wires, while the four taken in alternate pairs form together a complete and perfect two-phase system of wires.

My invention can best be understood from a contem tion with the following descriptionthereof.

In these drawings Figure l shows dtically ascheme of the system of connections, and- Fig. 2 is a vector diagram for illustrating the phase relations geo metrically. 1

In Fig. 1 there is shown av primary-transformer or transformer system for three-phase currents, composed of the three primary coils 1,2, and 8, connected in, delta-(t.hough not necessarilyso) the thresecond H mn 1-,'2'-, and 3-, imdalta, The of this transformer or system I is supplied with electric energy from a suitable source by meansof current-leads 4, 5, and 6. It will be understood of course that the relative phase-angle between theimpressed electromotive forces in the several coils 1 and 2, 2 and 3, and l and 3, of the transformer is in eachcasc 120 degrees of arc, and correspondingly the phase-angle between the impressed electromotive forces in the secondary coils l and 2, 2 and 3, and

1 and 3, will also be in each case 120 degrees of are.

From the system 1, 2, and 3 a set of four leads 7, 8,

9, and 10, are tapped at the points A, ll, and D respectively. Thesepoints are located as followszthe point A in the center of any of the three coils, say the coil 2', and the point C at the junction between the other'two coils, 1 and 3; the pointsB and D at intermediate points between the ends of the coils 3" and 1 respectively at equal distances electrically speaking from the point A, 'that is, from the respective ends of the coil 2. So taken, the points B and D are likewise at equal electrical distances from the point C, since the coils 1 and 3 are electrically equal, that is designed to produce electromotive forces of equal magnitude. As thus located, the three leads l3, C,and D form a three-phase system, the electromotive forces between which will be equal and at equal phase angles of 120 degrees each; and they may be tapped by any suitable translating devices adapted to that system, such as threephase motors E and lamps G. Also thefour leads A, B; C and D taken together in the pairs AC and 'BD form together a two-phase system having phase relations between the two pairs of 90 degrees, that is the electromotive force in the pair AC will be at right a'ngles'to that of the pair BD, and they may be tapped byany suitable translating devices such as two-phase motors F and lamps H equally divided between the two pairs of leads. In the two-phase system justdescribed, however, the electromotive forces in the're-' spective pairs, though at right angles, will not be of l equal magnitude unlessv the following condition is complied with: the points 13 and D must each be taken at an'electrical distance from the point C equal to k to 2 or 86.6% of the total electrical lengths ,of said coils; or in' other words, the electromotive force generated between the point C and the points B and D respect'ively. stands in each case in relationto the elec tromotive forces generated by the coils l and 3 respectively in the ratio ofk g to 2. Thereason-ior an explanation of this disposition may best be understood from a referenceto the vector diagram, (Fig. 2). In this diagram thesides C1, my, and 3 0 of the equilateral triangle Cry, represent respectively in magnitude and direction'the magnitudeand relative phase of the respective electromotivedorces generated by the .coilsl, 2", and 3. The reference characters 1, 2, and

,s-, which in Fig. l-apply m the coils, in Fig; 2 are up.

, force) BD, being the side of an equilateral triangle CBD,

, Again, bya well-lcnown geometrical-theorem, the line points B and D, the triangle CB1) or CBD, will be fore do not consider my invention limited by these prising a set of three inductive coils electrically energized plied conveniently to represent the electromotivevl forces generated thereby. As in Fig. l the point A bisects the line my representing the electromotive force 2, and the point C is at the-junction of the electromotive forces lfand 3; while the points B and D are intermediately situated upon the lines 1 and 3. It with the point C'as a center and radius CA circular arc BAD, be drawn said are will cut off from the lines (.x, Cy, (electromotive forces 1 and 3%) portions GB, GD, thereof which will be equal in length to the line (elebtromotivejforce) CA; and further the line (electromotive is also equal to the line (electromotiveiorce) CA,

(electromotive force) CA, being the median line of an equilateral triangle, is perpendicular to the line my, and I therefore to the line (electromotive forceiBD, which is parallel to therefore Gil is perpendicular to BD, hence electromotive forces CA'an Bl), arejat right angles. to each other and, equal magnitude, and therefore form a-trueand, equally balanced two-phase current-system,

It will be obvious that,- wherever the points B and D be taken, provided they be at equal distances from the point C on the lines Cy and (.x, as for example at the an equilateral triangle;and therefore the three leads 8, 9, and 10 will always form together a correct and equally balanced threephase system; and ,further that the electromotive forces CA, and BD, (or B" D) will in each case be at right angles to each other as regards phase, but will be of unequal magnitude unless the foregoing condition be complied with in which, 'Cl3=-CD=CA. Now it is well understood that the median of an equilateral triangle is to the side thereof as N 3 to 2;. hence it arises that GB. is to 1 also in the ratioof\ 3to2.' I i i Of course the skilled electrician will readily devise modified forms and electrical equivalents of the special arrangement of connections here shown, and I therefurther than is indicated by the reasonable scope of my claims, 1 Y

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is':

1.LA composite polyphase system of distribution comwith three-phase electromotive forces, and a set of four taps for distributing leads'connectd thereto, with the mutual electromotiv forces between three of said taps being' equal and at angles of 120 degrees of are, and the mutual electromotive force between two of said taps being at rightangles to the mutual electromotive force between the other two oi. said taps. 4 2. A composite polyphase system of distribution comprising a set of three inductive coils electrically energized with three-phase ele'ctromotive forces, and a set of four taps for distributing leads connectedthereto, the mutual electroniotive forces between three of said taps being equal and at angles of 120 degrees of are, and the mutual electromotive force between two of said taps being equal to and at right angles to themutual eleetroinotive force between the other two of said taps' ,3. A composite polyphase system of dlstributionconsisting of three equal inductive coils connected together in delta, means for energizing. said cells by a three-phase electromqtive force, and-a system of our 'leads tapped from said coils three of which carryelectromotive forces having a mutual phase-angle of 120 degrees, and two of which carry an electromotive force differing in phase-angle .otlier two.-

4. A composite polyphase system of distribution consisting of three equal inductive coils connected together in delta, means for energizing said coils by a three-phase electromotive force, and a system or vfour leads tapped by 90 degrees from the electrornotive force between the from said coils three of which carry electromotive forces having a mutual phase-angle of 120 degrees, and two of which earryan electromotive force differing in phase-angle by 90 degrees from' the electromotive force between the other two, the magnitude of the mutual electromotive force in the first pair being equal to that in the second pair.

A composite system of distribution-for polyphase cur rents comprising a set of three inductive coils-connected together in delta, means for generating three-phase electromotive forces within said'coils, and a set'of four current leads tapped to said cells as follows: the first lead at the junction of two of said coils, the second leadat the center of-the ,third coil, and the third, and fourth leads at intermediate points of the first two coils respectively.

6. A cdmpositelsystem of distributiol'i for poly-phase currents comprising a set of three inductive coils connected together in delta, means for'generating three-phase electromotive forces'within said coils, and'a set of four current leads tapped to 'said coils as follows: the. first lead atthe junction'or' two of said coils; the second lead at the center of the third coil, and the third and fourth leads at intermediate points of the first two;coi1s respectively, said in termediate points being so taken that they cut'ol! between them and the first point a portion of their respective coils whose electromotive force is to the electromotive force of the whole coil as 3 to .2.

Witnesses D. FERNANDEZ, JUAN R. CAMP.

WILLIAMT. TAYLOR.

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